The operation of circuit elements or components of a circuit may be influenced by the operating conditions of the circuit. Operating conditions may comprise, for example, a temperature of the circuit, a voltage supplied to a circuit and/or an age of circuit components.
The operating conditions of a circuit may affect the function of circuit components, for example, the operating speed of components. In order to allow a circuit to operate at a desired clock frequency, circuits are often designed to operate as close to failure as possible. While this has advantages in the speed at which a circuit is clocked, it may reduce the range of operating conditions under which the circuit can function without error.
While circuits may be designed to operate correctly in worst-case operating conditions, it can be difficult to predict how circuit components will behave under certain conditions. For example, small differences in the fabrication of circuits and materials used may influence the behavior of components under certain operating conditions. For example, even circuits from an identical fabrication batch may behave differently under the same operating conditions. It therefore may not be possible to accurately predict how a circuit component will behave under all operating conditions.